Known processes for producing a 4-halo-3-hydroxybutyronitrile include the following:
(1) 1,3-Dichloro-2-propanol is reacted with an alkali cyanide in an aqueous solution under heating (refer to JP-B-36-21718; the term "JP-B" as used herein means an "examined Japanese patent publication").
(2) 3-Chloro-1,2-propanediol is treated with tosyl chloride so as to tosylate the alcohol at the 1-position. Next, the tosylated product is reacted with an alkali cyanide (refer to JP-A-57-165352).
(3) Epichlorohydrin is reacted with hydrocyanic acid in the presence of a catalytic amount of potassium cyanide [refer to F. Binon et al., Bull. Soc. Chim. Belges, 72, 166-177 (1963)].
However, the process (1) can give only a limited yield (i.e., approximately 40%). The process (2) requires a complicated reaction procedure involving two stages and gives a low total yield (i.e., approximately 45%). On the other hand, it is difficult to control the reaction conditions for the process (3), wherein a dangerous chemical (i.e., hydrocyanic acid) is employed, so as to prevent the formation of side products. Thus, none of these known processes is advantageous from an industrial viewpoint. Furthermore, each of the processes (1) to (3) is a chemical one whereby no optically active product can be obtained from a prochiral or racemic starting material.